Interpretive Summary: Dust from cattle feedyards can be a nuisance to surrounding communities. One possible management practice for reducing dust emissions is to alter animal stocking densities. Dust concentrations upwind and downwind of feedyard pens stocked at two different stocking densities were measured and compared. Dust emissions measured from treatment pens having higher stocking densities were lower than those from the control pens. We conclude that stocking density is a viable management practice for controlling dust from cattle feedyards

Technical Abstract:
The moisture and compaction dynamics of an open-lot corral surface in a cattle feedyard depend strongly on the spatial density at which the animals are stocked. Because the moisture content and bulk density of the corral surface are directly related to its intrinsic dust susceptibility (B. Auvermann 2003) (Razote, et al. 2006), emission of fugitive dust from a feedyard surface should be sensitive to changes in stocking density. In the summer of 2012 we measured airborne dust concentrations upwind and downwind of feedyard pens stocked at two different densities, 718 (control) and 1,435 head per hectare, over a 160-day feeding period. Doubled stocking density was achieved in two different ways, by (A) confining cattle to half the pen area using electric cross-fencing and (B) doubling the number of cattle in the pens. Path-averaged dust concentrations were measured upwind and downwind of feedyard pens using an optical particle sizer and an earlier-model optical sensor mounted on mobile monitoring platforms. Downwind 1-minute concentrations of dust varied from 1 to 4,478 micrograms per cubic meter for the control pens, 1 to 2,431 micrograms per cubic meter for the pens with cross-fencing (treatment A), and 1 to 2,872 micrograms per cubic meter for the pens with twice as many cattle as the control pens (treatment B). Dispersion modeling using AERMOD revealed that the apparent dust-emission fluxes from treatments A and B were 79.4 and 80.6% lower, respectively, than the apparent emission flux from the control pens. We conclude that stocking-density manipulation is a viable Beneficial Management Practice (BMP) for controlling fugitive dust from open-lot cattle feedyards